1. Field of the Invention
The present invention relates to a scroll type compressor that changes the volumetric capacity of a compression space formed with a fixed scroll member and an oscillating scroll member to compress an on-board coolant.
2. Related Art
In scroll type compressors of the related art, in which a compression space is formed by a fixed scroll member and an oscillating scroll member and the oscillating scroll member makes an oscillating movement relative to the fixed scroll member, the lubrication and sealing of the two members at the sliding contact surface are crucial factors.
Accordingly, the scroll type compressor disclosed in Japanese Patent Unexamined Publication 3-149391, for example, includes a rotary displacement type oil pump in its structure, so that a sufficient quantity of oil can be reliably supplied to the bearings regardless of the flow rate of the lubricating oil supplied to the compression work space. With this, a large quantity of lubricating oil can be assured even when high loads are applied to the revolving drive bearing, eccentric bearing and the first main bearing.
However, in the above example, if, in order to achieve a reduction in the weight of the compressor and a reduction in cost, the fixed scroll member and oscillating scroll member are made of a material other than a material, such as aluminum, for example, a problem arises. Because of the high back pressure on the oscillating scroll member, it is pressed towards the fixed scroll member, and as a result, the sliding area where the oscillating scroll member and fixed scroll member are in contact with each other tends to seize. To eliminate this problem, a thrust bearing for the drive shaft (hereafter referred to as "thrust bearing") is provided to bear the load applied to the drive shaft.
However, when the load is large, the thrust bearing itself can seize and also, as the load is applied constantly, the service life of the thrust bearing is shortened.